Part A
AD7655ASTZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 5580 PCS
- Package
- LQFP-48
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7655ASTZ and AD7652AST are both 16-bit successive-approximation ADCs from Analog Devices in the same 48-lead LQFP package, sharing a comparable analog input range and serial interface, so the AD7652AST can serve as a functional substitute for the AD7655ASTZ in many designs. However, the AD7655ASTZ provides four simultaneous-sampling input channels versus a single channel on the AD7652AST, and the two devices differ in throughput rate and power consumption. Engineers should validate channel-count requirements, sampling rate headroom, and power budget before adopting the AD7652AST as a drop-in replacement.
Channel Count
Validation required
Package Type
High match
Sampling Rate
Validation required
Resolution
High match
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD7655ASTZ | AD7652AST | Why it matters |
|---|---|---|---|
| Number of ADC Input Channels | 4 (2 differential / 4 single-ended, multiplexed) | 1 (single-ended) | Channel count determines how many signals can be digitized; the AD7655 supports multi-channel multiplexed acquisition while the AD7652 handles only one input. |
| Resolution | 16 bits | 16 bits | Both provide 16-bit resolution, so precision and dynamic range are equivalent for substitutability in that respect. |
| Sampling Rate | 500 kSPS | 500 kSPS | Identical throughput means both can meet the same acquisition bandwidth requirements. |
| Input Configuration | Pseudo-differential / true differential selectable | Single-ended | Differential inputs improve noise immunity and common-mode rejection; the AD7655 offers flexibility the AD7652 lacks. |
| Interface Type | Parallel and Serial (SPI/QSPI/MICROWIRE/DSP) | Parallel and Serial (SPI/QSPI/MICROWIRE/DSP) | Matching interface options allow either part to connect to the same host processor bus without redesign. |
| Supply Voltage (Analog) | 5 V | 5 V | Same analog supply simplifies power rail reuse when swapping parts. |
| Package | 48-Lead LQFP | 48-Lead LQFP | Identical package and pin count enable drop-in board compatibility. |
| Power Consumption | Approximately 120 mW typical | Approximately 100 mW typical | Lower power in the AD7652 benefits thermally constrained or battery-powered designs. |
| Internal Reference | Yes (2.5 V on-chip reference) | Yes (2.5 V on-chip reference) | Both include an internal reference, reducing external component count equally. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7655ASTZ | AD7652AST |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 1M | 500k |
| Number of A/D Converters | 1 | 1 |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Number of Inputs | 2, 4 | - |
| Input Type | Pseudo-Differential, Single Ended | - |
| Data Interface | SPI, Parallel, DSP | - |
| Configuration | MUX-S/H-MUX-ADC | - |
| Ratio - S / H: ADC | 2:1 | - |
| Architecture | SAR | - |
| Reference Type | External | - |
| Voltage - Supply, Analog | 5V | - |
| Voltage - Supply, Digital | 5V | - |
| Features | Simultaneous Sampling | - |
Frequently asked questions
What are the primary differences between the AD7655ASTZ and the AD7652AST?
The AD7655ASTZ is a 16-bit, 1 MSPS, dual-channel simultaneous-sampling successive-approximation ADC with two on-chip track-and-hold amplifiers, while the AD7652AST is a 16-bit, 500 kSPS, single-channel successive-approximation ADC with one track-and-hold amplifier. The AD7655ASTZ provides two simultaneous-sampling inputs at twice the throughput, whereas the AD7652AST provides a single input channel at half the throughput.
Are the AD7655ASTZ and AD7652AST pin-compatible?
No. Both devices are offered in 48-lead LQFP packages, but the AD7655ASTZ uses two analog input channels with separate track-and-hold circuitry and a different pin function assignment than the single-channel AD7652AST. The pinouts are not interchangeable, so PCB layouts must be designed for the specific device.
Can the AD7652AST be used as a drop-in replacement for the AD7655ASTZ?
No. The AD7652AST is a single-channel, 500 kSPS converter, while the AD7655ASTZ is a dual-channel, 1 MSPS simultaneous-sampling converter. The channel count, throughput, pinout, and analog input architecture differ, so a direct drop-in substitution is not possible without redesign and validation against the respective datasheets.
What are the maximum sampling rates of the AD7655ASTZ and AD7652AST?
The AD7655ASTZ has a maximum throughput of 1 MSPS. The AD7652AST has a maximum throughput of 500 kSPS. Both are 16-bit successive-approximation ADCs, but the AD7655ASTZ provides twice the conversion rate of the AD7652AST.
Do both devices support simultaneous sampling?
Only the AD7655ASTZ supports simultaneous sampling. It integrates two track-and-hold amplifiers that sample two analog inputs at the same instant, which is suitable for applications requiring phase-coherent acquisition of two signals. The AD7652AST has a single track-and-hold amplifier and a single analog input channel, so it does not provide simultaneous multi-channel sampling.
What analog input configurations do the AD7655ASTZ and AD7652AST support?
The AD7655ASTZ provides two analog input channels, each with its own track-and-hold amplifier, supporting simultaneous sampling of two single-ended or differential signals depending on configuration. The AD7652AST provides a single analog input channel with one track-and-hold amplifier. Designers should consult the respective datasheets for the exact input voltage ranges and configuration options.
What package types are used for the AD7655ASTZ and AD7652AST?
Both the AD7655ASTZ and the AD7652AST are offered in 48-lead LQFP packages. The package style is the same, but the internal channel architecture and pin functions differ, so the devices are not pin-for-pin interchangeable.
Which device is better suited for multi-channel simultaneous acquisition applications?
The AD7655ASTZ is better suited for multi-channel simultaneous acquisition because it integrates two track-and-hold amplifiers and two analog input channels that sample at the same instant at up to 1 MSPS. The AD7652AST, with a single channel and 500 kSPS throughput, is intended for single-channel acquisition and would require external multiplexing and additional synchronization for multi-channel simultaneous sampling.